The invention relates to a device for ensuring safe movement of a moving part.
The invention is particularly applicable to angle-of-attack sensors used in aeronautics. Such sensors are mounted on the skins of aircraft to measure the angle of attack of an airflow with respect to the aircraft. These sensors contribute to the safety of the aircraft's flight. In particular, they make it possible to prevent stalling. They are generally located in the front part of the aircraft, frequently in a horizontal position (a position called “3 o'clock” or “9 o'clock”). Such a sensor can comprise a moving vane rotatable about an axis perpendicular to the skin of the aircraft. The moving vane is orientated in the axis of the surrounding airflow. The orientation of the moving vane enables the angle of attack of the aircraft to be determined. The vane forms an appendage located on the exterior of the aircraft skin. As with all appendages, there is a considerable risk of damaging it during ground maintenance operations on the aircraft.
An impact on the moving vane may be received in any direction, and this direction would have to be exactly in alignment with the plane of symmetry of the vane for the vane not to rotate. Moreover, such an impact tends to deform the vane in a direction in which its inertia is greatest. This impact is therefore very unlikely to damage the general shape of the vane and will only deform its leading edge. Such deformation is always visible. Consequently, only those impacts which are capable of causing the vane to rotate will be considered below. These impacts are responsible for the significant damage which may be caused to the vane. Furthermore, these impacts can distort the vane, resulting in incorrect measurement of the angle of attack. Moreover, this type of deformation is not easily seen.
A moving vane cannot rotate fully through 360° about its axis of rotation. The rotation is limited by stops, allowing, for example, a range of the order of 90°.